The discovery of tuberculosis (TB) in two patients with SARS raises concern that the latter disease may somehow increase susceptibility to the former, according to researchers from Singapore.

SARS or severe acute respiratory syndrome wreaked havoc on China, Hong Kong, and other countries across the world last year. The disease was found to be caused by a microbe called a coronavirus.

In the journal Clinical Infectious Diseases, Dr. J. G. H. Low and colleagues, from Tan Tock Seng Hospital, describe two men who developed TB in association with SARS, “a phenomenon not previously reported.”

The occurrence of two cases of TB among 236 patients with probable SARS, far exceeds the TB rates typically seen in the general population of Singapore, the authors note.

In both cases, TB only came to light after full recovery from SARS, when the patients developed persistent lung symptoms and worsening chest X-ray findings. It is “highly likely,” the team notes, that both patients developed TB after acquiring SARS.

The investigators suggest that the SARS coronavirus temporarily suppresses the immune system making it harder for people to fight off the TB microbe if exposure occurs.

SOURCE: Clinical Infectious Diseases, June 15, 2004.